Bar soaps remain a popular product form for cleansing skin. Those skilled in the art use the term soap to designate the reaction product of a carboxylic acid with a base, typically a metal hydroxide or carbonate. The resulting salt has both a polar hydrophilic end and a non-polar lipophilic end which facilitates the removal of oils and other non-polar materials from the skin or other surface in the presence of water.
Bar soaps are customarily prepared either by framing/casting or by milling/plodding. The process of making bar soaps usually requires a drying step to remove the “gummy” texture and excessive pliability of the soap mass which exist typically at higher moisture levels. Finished bar soaps typically will thus have a relatively low level of moisture (i.e. water), usually in the range of from about 10% to about 14% by weight of the bar soap. However, developments have been made with respect to achieving bar soaps that contain higher moisture levels, e.g. at least about 15% water by weight of the bar soap. Bar soaps having higher levels of moisture can be desirable with respect to formulation and process efficiency. However, upon storage in conventional paperboard packaging, high moisture bar soaps tend to encounter of number of potential problems. These problems include moisture loss (via evaporation or absorption into the paperboard packaging material), mold growth on the paperboard packaging material, and the development of colored stains on the bar soap and packaging resulting from chemical reaction between the high moisture bar soap and the paperboard, especially recycled paperboard.
There thus remains a desire to develop a package for a high moisture bar soap to alleviate the problems of moisture loss, mold growth and dye transfer.